A method of and apparatus for locating and detecting a fingerprint deposited on a surface, the method comprising setting up an electric field such that a differential charge density is produced coincident with the location of a fingerprint deposited on the surface. In the fuel cell, the separators each are in the form of a flat plate of synthetic resin integrally provided with a plurality of spaced projections made of pressed carbon powder and retained in contact with the electrode plates to form a pair of reaction chambers at opposite sides of each of the electrolytic membranes. Such compounds may especially be used in the production of printed wiring boards. The list of sample, common words is ordered based on frequency of correlation in common usage, the most common being designated as the default sample word, and the user is first presented with a subset of the words in the list which are most likely to be selected. These molecules generally comprise an antigen binding site of an antibody and at least a portion of a transmembrane domain of a cell surface receptor.